Five years ago, Dawn Blezard went for what she thought was a routine eye test.
But the examination revealed she had a rare genetic condition that would eventually cause her to go blind.
The 49-year-old yoga teacher from Sudbury, Suffolk, was diagnosed with Stargardt's disease and has already lost vision in her left eye, with the other deteriorating.
While the condition has already affected her life, she is not letting it stop her from taking on the 40km (24 miles) Yorkshire Three Peaks Challenge.
Mrs Blezard said she hoped the challenge would show others they too can take on anything they put their minds to.
Mrs Blezard's routine eye appointment offered her the chance to pay a small additional fee to have the back of her eyes scanned to check their health.
She agreed and after it was done she was told to wait outside which she first thought was "unusual".
"They called me back in and this lovely lady said to me, 'Oh my God, I'm so excited, I've only ever seen this in textbooks. You've got a rare eye disease and you've got it on both eyes'," she explained.
"After that it was kind of a whirlwind."
Three weeks later, she was diagnosed with Stargardt's disease, which affects one in 8,000 to 10,000 people.
She was told there was nothing that could be done to save her vision and she is now registered as visually impaired.
As well as losing her vision, Mrs Blezard can no longer drive and she makes use of a guide cane.
"I've fallen down flights of stairs and broken my ribs because you have no depth," she continued.
"As it's deteriorated, it's like a photo – there's no depth, things are quite pixelated so you're living in a filtered world all the time."
Mrs Blezard said she had adapted however and she still continues to teach yoga.
"My world has changed, but I'm not giving up," she added.
'Why next year?'
After her diagnosis, Mrs Blezard discovered the Macular Society who she said answered the phone immediately and helped support her.
For years, she had always wanted to take on the Yorkshire Three Peaks Challenge, but had "always put it off".
"[My condition] has really made me think, well why next year? Why not this year? Because we don't know what could happen next year," she said.
Mrs Blezard decided to take the challenge on for the Macular Society.
She will set off at 08:00 BST on Saturday and will be joined by members of her yoga community from Sudbury Leisure Centre and from the Self Centre in Bury St Edmunds.
They will do the walk over two days to accommodate her sight and she said she was "excited" to get going.
